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Intense Rainfall More Common in last 20 Years

Submitted by Kelly Palmer on Fri, 06/23/2017 - 11:07

Intense rainfall events, like the one that triggered flash floods throughout the region and a mudslide in southern Vermont on Monday, have become much more common in the last 20 years, according to researchers at Dartmouth College.

Though the jury is still out on whether climate change is behind the trend, the findings, which were published last month, do suggest that what we think of as 100-year flood events might actually be much more likely to happen than conventional wisdom suggests, said Jonathan Winter, who joined Dartmouth colleagues Huanping Huang and Erich Osterberg on the research team.

Winter found that intense rainfalls — generally thought of as 2 or more inches of precipitation in a 24-hour period — are 53 percent more likely to happen than they were before the mid-1990s.

And current conditions in the Upper Valley are likely to increase the impact of those heavy rains.

“One would expect it to have a bigger flood potential, because the soil’s already saturated,” he said on Monday, just as the National Weather Service was stepping up warnings about potential flash floods throughout much of the Northeast. “The river is already up, as opposed to if we had a drier spring.” See more articles: